Manufacture of india-rubber boots and shoes.



PATENTED FEBlv 11, 1908.

A.fs0BULZB. MANUBAGTUBB 0B INDIA BUBBBB BOOTS AND sHoBs.

APPLICATION FILED 0CT.10. 19 04. RENBWED NOV.l.1907.

2 SHEETS-SHEET 1.

No. 878,749. PATENTED PEB. 11, 1908.A

A.' SCHULZB. MANUFAOTURE OP INDIA RUBBER BOOTS AND SHOES.

l `APPLICATION FILED OGT.10. 1904. BENEWBD NOV. 1, 1907.

2 SHEETS-SHEET 2.

sse.- jue/(for f4 mm f UNITED 'STATES PATENT ortica..

' ANDREW SCHULZE, oF WAsnI'NGToN, DISTRICT or COLUMBIA.

' MaNUFAc'rURE or* INDIA-reclaman io'rs ND SHOES.

Specification of Letters Patent.

Patented Feb. 11, reos.

Application 'led October 10. 1904. Serial No. 227.907. Renewed November 1. 1907. Serial No. 400.152.

' To all 'whom it may concern:

Be it known that I, ANDREW SCHUHE, a citizen of the United States', residing in the lcity of Washington, District of Columbia,

inflated boot or shoe upon a last, then inclos- I ing the last Within a olosabl mold and exteo pandin the boot or shoe against the heated Walls o the mold, for 'the purpose of vulcanizing the boot or shoe.

i My present invention relates' to an i'm provement upon the invention shown in my former application referred to, and, in its main aspects, is applicable generally to the manufacture of india rubber boots and shoes, p

as Willjhereinaf'termore fullyappear.

In the machine of my former application referred to, thecom ressed air utilizedfor expanding the unvu canized boot or shoe' against the heated sides of the mold is admitted into contact with the interior of the boot or shoe. In view of the fact that the air is under considerable compression, it is necessary, under these circumstances, that the mold shall close tight; otherwise, the compressed air would rupture theblank at any o en or partiallyo'pen joint. lOn the other and, it is found, in practice, that When the mold is tightly closed, the vulcanized product frequently exhibits irregular inderitations or depressions upon its exterior surface, which lessen -the commercial value of the product, and sometimes render it alto-` gether unsalable. These depressions or indentations are, in my opinion, due either to ,the entrappirlilg( of air in'the mold .as it closes uponthe -bla carried'by the last, or tothe generation of va ors or gases from the india rubber stock of t e blank, or to both of these occur wherever the admission of air directly causes. The same difficulty must inevitably to the inner surface of the blankrequires the 3. em loyment of a tightly closing or substantia y tightly closing mold; inasmuch as the air, vapors or gases, finding no vent, hold portions 'of the blank away' from the heated surfaces of the mold and reproduce themselves in the form ofthe depressions orl recesses referred to.

In the practice of my present invention, `I

-provide a last, as in my former'application referred to, and upon this las't I stretch or fit the unvulcanized boot or shoe to be vulcanized. The last which I -employ,`however,

'the admission of compressed air between the main body portion of the last and the air tight covering, the covering will be'mfiated and will force the rubber boot or shoe against the innerheated surfaces of the mold. By Y this expedient, with the employment of a vcom arati'vely small amount of compressed air, obtainan immediate inflation of the rubber boot or shoe and any air, vapor 0r gases that may be entrap ed or that may be generated within the molld, are given ample opportunity to vent themselves through the mold joints, which are not required to be closed air tight, but which may be left open to the extent of several thousandths of an inch Without injury'to the final product. To lessen the tendency to the formation of important fins at the joints, I referably make the flexible covering of two Iayers, the inner,

one being of india rubber, and the outer one of stockinet or other` similar fabric having a limited degree of exp ansiblity and Which Will therefore -correspondinglylimit the expan sion of the inner rubber layer of thecovering. By the employment of the aluminium shield described In lm former application, I amenabled to entire yavoid the production of any fin Whatever along the top surface of the boot or shoe.

In the -accompan ing drawing, Figure 1 represents a lcentral l ongitudinal section of a the vulcanizing mold, i rshown in section and ot er portions in Aelevation. Fig. 2-represents-a section and' artial elevation on the line 2-2 of Fig. `1. igs. 3

and 4 represent exterior views of the covered 'e last with edge-formers of differing confi uration applied thereto. Fig. 3 is a deta' section through the ed former shown in Fig, 3.

Referring to thel rawin A and B indicate the side portions and C lndidates the sole I* will be readilya arent, and r ifiil effect. llir which last may be, if desired, made ho low as shown in Figs. 1 and 2, for the sake of lightness. It consists of the main body portion E, in combination with a flexible covering,

applied to its outer surface, and consisting, preferably, of an inner layer a of ex ansible rubber and an outer layer b of stoc inet or similar fabric having a limited degree of elasticity.

In my preferred construction, the flexible covering is so arranged as to envelop the entire last, and, in this event, it may, or may not be provided with an addition al outer sole plate c of metal having the function of causing a sharper imprint upon the sole than could otherwise be conveniently obtained It is feasible, however, to omit the covering upon the sole portion of the last and upon the wall d opposite the sole portion, provided the covering -is sufficiently overlapped and held so as to inclose in an air tight manner the remainder of the last, when molds are employed of the kind wherein the metal sole portion of the last is brought into direct contact with the interior surface of the boot or shoe to be vulcanized. In general, however, it will be found ex edient to cover the entire last with the two ayer covering, and, if ythe plate c is employed, to rigidly connect said plate in place. I v

To the interior of the air ti ht covering, compressed air may be admitter through the tube D. The interior bore of this tube preferably terminates-at a point opposite the radial o enings e, although it may continue on into t e hollow interior of the last, if so desired. I prefer, however, to have it termi-A nate at a point opposite the radial o enings. of ports e, for the reason that by so oing, I greatly limit the amount of compressed air necessary to each vulcanization oeration, as

o uce a more direct and powe '1n the radial openings e the compressed air passes through ports f made in the walls of the last and thus gains access to the space between the flexible covering and the outer surface of the last'. As a consequence, the flexible covering is im-. mediately forced outward and with it the india rubber boot or shoe F, against the heated surfaces of the closed molr Any air, vapor or gas resentin the mold or generated therein is ee to escape through the joints of the mold1 which are purposely left sufficiently open for that purpose, although, as will be readily understood, this venting does not require that the joints be open for a v`width of more than from one to say four or five one-thousandths of an/inch, as the case maybe. j

In order to give a suitable finish to the mouth'edge of the shoe, and particularly to obviate the"`-tendency of the compressed air to unduly diminish the thickness of the may of the form known commercially as a storm shoe, i. e. a shoe having a front portion adapted to come u well-over the lacings of the inner leather s oe, I give to the dam or former the general configuration shown in Figs. 1, 2 3 vand 3a of the drawings. Whereas, if a low quarter rubber shoe is to be 1nade,.I give to the dam or former a corresponding con figuration for that particular make of shoe, as shown in Fig. 4. f

The dam or formerreferred to is indicated by the letter g in Figs. 1, 2 and 3 and 3a and by the letter g in Fig. 4. It is preferably provided on its inner edge with a continuous groove, as indicated in Figs. 3 3 and 4, so as to form a corresponding bead upon the mouth edge of the shoe, and, of course, whether the groove is present or not, to correspondingly thicken the shoe along the mouth edge, so as to reinforce ,it thereat, as is desired.- The dam or former ma be made of any suitable material. If ma e of metal or other like infiexible material, its exterior surface is so finished as to make contact with the sides of the mold when the mold closes upon the last, in which event, the com- ,bei cause ofthe compressibility of the flexible covvering. In order, however,to avoid theinconvemence and expense of carefully fitting a metal dam to the mold, I preferably employ, as l indicated in Fi s. 1 and 2',a dam or former of rubber having just sufficient ex ansibility to be forced out into contact wit the sides of the mold by the action of the compressed air during the vulcanizing operation, but suffi' ciently `incom ressible to retainsubstantiall its orlglnal e ge thickness as against the a1r pressure. By this expedient, without fashioning the dam or former so as to make an accurate fit with the closi sides of the mold, I obtain the same resulily employing the pressure .of the incomi necessary closure'. It wi l, of course, b`e evident that the same`metal last having a flexible covering of the kind described ma be employed for the vulcanization of shoes aving different mouth openings, by merely re-` moving one form or configuration of dam or former and substituting another therefor.

air to obtain the4 To this end, it will be convenient to attach the dam or former to the covering by means of cement, so that it can be removed when desired and anothersubstituted in its place. It is, of course, apparent that the dam or former can be, if desired, made in sections and applied to the closing sides of the mold or that it may be in part located upon the last and in part u on the mold; but, for most purposes, it wi be found more convenient to attach it directly to the last, as illustrated.

,In operation, the workman, having built up the unvulcanized shoe upon the covered last, places the last upon the extension h of the tube D, and causes the mold to close, for instance, by the means described in my former application hereinbefore referred to. With the closing of the mold, the compressed air is admitted through the tube'D and enters between the flexible covering and themetal main body ortion of the last, thereby forcing the unvu canize'd shoe out against' thev heated surfaceof the mold and thereby effecting its vulcanization. At the same time, the thickened edge or bead around the mouth of the shoe is made by the dam or former, and any air that has been entrapped in the mold or any vapors or` gases that may4 be generated from the` india rubber stock escapes through the mold joints, which serve as sufficient vents for that purpose.

Having thus described my invention, whatV I claim is z- 1. 'In apparatus for vulcanizing india rubber boots and shoes, a last, provided with a flexible covering, and means for introducing pompressed air betweenfthe covering and the ast.

2; In an apparatus for vulcanizing india rubber boots and shoes, a last provided with a flexible covering, a sole late, and means for introducing compresse air between the covering and the last, substantially asdef scribed.

3. In apparatus for vulcanizingindia rubber boots and shoes, a last, provided with a flexible covering, a mouth edge dam or.

-ber boots and shoes, a last, provided with a flexible covering consisting of an inner layer of rubber and an outerlayer of fabric, and means for introducing compressed air between the covering and the last.

6. In apparatus for vulcanizing india rub-4 ber boots and shoes, a last, provided with a flexible covering, a mouth edge dam or -former of expansible material, and means for introducing compressed air between the covering and the last.

7. In apparatus for vulcanizing india rubber boots and shoes, a last provided with a flexible covering, inlet openings passing through the last to the interior surface of the covering, 'and a supply tube for compressed air communicating directly with said inlet openings; substantially as described.

8. Apparatus for vulcanizing india rubber boots and shoes, com rising' a last havin a flexiblecovering, a c osable mold for sal last, and means for introducing com ressedl air between the covering and the ast directly from the inlet pipe; substantially as described.

lIn testimony whereofl afiix my signature,

in presence of two witnesses.

p ANDREW SCHULZE.

Witnesses: y

WILLIAM G. HOWELL, CHARLES LOWELL HoWAnD. 

